Manufacture of strengthened glass.



v,wza B I %f% E. BENEDICTUS.

MANUFACTURE OF STRENGTHENED GLASS 1 APPLICATION FILED JUNE 14, 1911.

1L 1182fi89 Patented May 9,1916.

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11v vE/v TOR WITNESSES EDOUHRD BENED/CTUS meanest.

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MANUFACTURE OF STBENGEE'D GLAS S.

Specification or Letters Patent.

Patented may 9, 19916..

Application filed June 14, 1911. Serial No. 633,123.

To all whom it may concern Be it known that I, 'EDOUARD BENEDICTUS, of 25 Rue de Fourcroy," Paris, France, artistic painter, have invented certain new and useful Improvementsin the Manufacture of Strengthened Glass, of which the following is a full, clear, and exact description.

This invention relates to a new process sary by the application of pressure and without requiring the use of a solvent to soften the surfaceswhich are to be stuck together. Nevertheless gelatin is a hygroscopic substance whichv in spite of attempted drying may easily retain moisture which prejudicially affects the solidity and the.

transparglcy of the finished strengthened glass.

jecting the gelatin at the moment of sticking, to a liquid which is both hygroscopic and volatile, in such a way as to dehydrate the gelatin and then to remove by evaporation at the same time as the water the air which remained therein during the sticking- Moreover, it is advantageous to employ for this purpose a liquid which is inert to gelatin, that is neither dissolving nor attacking that, substance, so that it may beexpelled rapidly under the action of heat which is not the case when a solvent which-incorporates itself'therein is used to soften the surface of the gelatin; in the latter case the last traces of the solvent are diflicult to eliminate.

The liquid employed is preferably ethyl alcohol of 95%, denatured or not. If denatured alcohol is used for economy, methylic denaturation is the method to be preferred. The figure of 95% above given is only by way of example, but it is advisable not, to

dried without being The present invention consists in sub-' lower the strength below 75%, because there would then be produced a fog caused by moisture in the gelatin.

lhe following example method of making strengthened glass according to this invention: In the first place the face of the glass plates which is to contact with the gelatin is cleaned as thoroughly as-possible; this is important to insure the perfect adhesion of the gelatin upon. the glass. The cleaning may be effected by usingrouge or tripoli in suspension in water; the glass is then rinsed and touched. Other methods of cleaning may of course be employed. The glass plates are'then' dipped in a bath of ethyl alcohol and applied on describes a' either side of the sheet .of gelatin. The

whole is then, laid between the tables of a hydraulic or other press heated by steam or water circulationand a pressure of several. kilograms i (for example eight kilograms) per square centimeter is applied. The heat softens the gelatin anditsaction combined with that of the pressure efiects the sticking of the same to the glass, while -the liquid is expelled together with the moisture of the gelatin and the contained am In place of ordinary gelatin, there may be employed gelatin which is bleached and rendered supple andtenacious by incorporation of albumin, fibrin and protein or also nitrocellulose, as indicated in the specification of my application for Letters Patent filed June 13, 1911, Serial No. 632,850.

. Instead of preparing the .sheet of gelatin beforehand, the material may be poured upon one of the glass plates, the-whole beglass plate'applied under heat and pressure. -When the glass is to be strengthened by ing then dipped in alcohol and the second a layer of celluloid coated with gelatin, the latter is substituted for the gelatin sheet as indicated in the above mentioned specification, the method of attaching this strength: ening layer between the glass-plates being identical with that described in the case of gelatin alone. But in this case it is advantageous to adopt the following procedure: Upon eachvof the well-cleaned glass plates there is poured an aqueous solution of gelaof gelatin. The two glass, plates are dipped in alcohol and there is inserted between them '(on. the side of the gelatin film) a sheet of celluloid; the whole is then submitted to heat and pressure as above described. The alcohol in this way introduced between the gelatin and the celluloid exerts no appreciable solvent action upon the celluloid under the conditions of this method of operation, but as above stated the alcohol dehydrates the gelatin and removes the air contained between the celluloid' and the gelatinized faces of the glass.

To insure the preservation of the strengthened glass so made, and to prevent rehydration of the gelatin as Well as any return of air between the gelatin and the glass along the periphery of the strengthened glass, the edges of the sheet may be luted. This luting may be effected for example by insolubilizing the periphery of the gelatin "sheet by one or other of the following processes or any equivalent :The strengthened glass is dipped for three hours in a saturated solution of bichromate of potash; the latter 'penetratesinto the gelatin for an approximate distance of two millimeters and after exposure to sunlight it becomes insoluble and forms a sound joint. The glass is exposed for some days to vapors of formol which penetrate by diffusion for eight to ten millimeters and render the gelatin insoluble. tween the glass plates, its edges are dipped in a saturated solution of bichromate of potash and after the making ,Of the strengthened glass it is exposed to sunlight;

this luting is hermetic. maybe effected by applying paraflin, pitch or the like along a marginal space afl'orded all along the periphery of the sheet of armored glassby the use of a layer of strengthening material of slightly smaller dimensions than the glass'plates.

One or other of the above processes will be 'employed according to circumstances. For example the second process (by means of formol) will be applied to glass re-cut 'or retrimmed to size, while the others will.

she applied preferably toglass ofmdefinite dimensions, such as windows for carriages,

conservatories, railways and the like.

In the accompanying drawing, Figure 1 is a section through reinforced glass in which the two glass sheets are united by a sheet of gelatin aloneyFig. 2 is a like view in which a sheet of celluloidis-interposed between gelatin sheets on-the adjacent faces of the 'two sheets of glass.

In these drawings a. and I) represent the sheets of glass between which is interposed afsheet of gelatin 0, inFig. 1, and two films o celluloid d, in the form shown in Fig. 2.

Having thus described my invention, what Before inserting the gelatin be Again the luting gelatin 0 and c-,separated by a film of 1. The'process of reinforcing glass, which I gelatin between sheets of glass in the pres ence of heat and a volatile, hygroscopic liquid inert to gelatin, substantially as and for the purpose described.

2. The process of reinforcing glass, which consists in treating asubstance comprising gelatin with a volatile, hygroscopic liquid inert to gelatin, and immediately pressing said substance between sheets of glass in the presence of heat.

8. The process of reinforcing glass, which consists in treating a sheet comprising gelatin with ethyl alcohol almostfree of water (alcohol approximately at 90-95%) and immediately pressing said sheet between sheets of glass in the presence of heat. 1

.. consists in pressing a substance comprising I 4:. The process of reinforcing glass, which consists in subjecting a sheet of reinforcing material comprising gelatinto the action of a volatile, hygroscopic liquid-inert to gelatin and at once compressing said sheet between sheets of glass 1n the presence of heat.

5. The process of reinforcing glass, which] consists in subjecting a sheet ofv reinforcing material comprising gelatin to' the action of a volatile, hygroscopic liquid inert to gelatin and at once eompressingsaidsheet between sheets of glass in the presence of heat, and thereafterlu'ting the edges 'ofthe article thus produced to prevent-the rehydration of I in advance of saidpressure, for the purpose" described. v I

7. The process of reinforcing fglasswhich consists in subjecting to pressure in "the presv ence of heat a composite comprising a sheet of celluloid, a film of gelatin -on each side thereof and sheets of, glass outside the gelatin, the gelatin being subjected to.the'action of a volatile, hygroscopic liquid inert to gelatin immediately in advance of said pressure, for the purpose described.

8. The process of reinforcing glass which consists in assembling a sheet of celluloid between two sheets of glass',.each of the latter having on its juxtaposed face a film of gelatin, and subjecting said composite to pressure in the presence of heat and in the presence of a volatile hygroscopic liquid incontact with 'the gelatin, or the purpose described.

9. The. process ofreinforcing glass which consists in assembling a sheet .of celluloidbetween two sheets of glass, each of the latter having on its juxtaposed face a film of gelatin, andsubjecting said composite to pressure in the presence of heat and in the presence of a volatile hygroscopic liquid in contact with the gelatin and inert thereto, for the purpose described.

10. The process of reinforcing glass which consists inapplying a solution of gelatin to the faces of glass sheets, permitting the solution to dry whereby a film of gelatin is formed on the faces of said sheets, dipping said sheets in a bath of volatile hygroscopic liquid, immediately assembling a sheet of celluloid between them adjacent the gelatin and subjecting the composite to pressure in the presence of heat.

11. The process of reinforcing glass which I consists in applying a solution of gelatin to the faces of glass sheets, permitting the solution to dry, wherebv a film of gelatin is formed on the faces of said sheets, dipping said sheets in a bath of volatile hygroscopic liquid inert to gelatin, immediately assembling a sheet of celluloid between them adj acent the gelatin and subj ecting the composite to pressure in the presence of heat.

12. As a new article of .manufacture, a sheet of celluloid faced on both sides and in the order named by sheets of gelatin and glass, all rigidly and autogenously united together, and the gelatin being substantially free from contained moisture, as described.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses.

CHARLES DoNY, LEON PEILLET 

